Almost six weeks after Melbourne's grand final loss, club great Smith remains unsigned.

Smith's manager Isaac Moses is reportedly attempting to bolster the former Kangaroos captain's one-year deal with third party arrangements with Melbourne resisting.

While the Storm are confident they will find common ground for Smith to play an 18th NRL season to become the first NRL star to break the 400-game barrier, Kimmorley said Melbourne should get the deal done.

"He's been the best player that club's ever had and probably the best our game's ever seen and a big reason for their long-term success," said Kimmorley, who played 79 games over three seasons with Melbourne including their 1999 title.

"He also stood down from Origin this year as well which helped them win every game through that period.

"With the service he's given them and the value of what he gives the club - they need him more than ever without Billy (Slater).

"I would have thought they'd do as much as they could and do it as quickly as they could to get the deal done."

Kimmorley felt the club would miss Slater, who retired at the end of the season, even more than they did fellow great Cooper Cronk, who left at the end of 2017.

He said he feared for the club's future if they lost Smith at the same time as Slater.

"Billy is a one in a generation player and has changed the way fullbacks play," he said.

"If they can stagger and lose Cameron next year it's a better position than now."

Kimmorley said if the deal wasn't done it would be sad to see 35-year-old Smith bow out with his last game being the grand final defeat by the Sydney Roosters.

"I don't expect the club to break the bank but I wouldn't have thought Cameron would have been going above and beyond either," Kimmorley said.

"You're not saying he's over the hill or by re-signing him they'll be going backwards - he's still the best hooker in the game."

Australian Associated Press